Apparatus for slaking lime.



No. 664,440.y Patented Dec. -25, |900. W. SCHULTHESS.`

APPARATUS Fon SLAKING LIME.

3 Sheets-Sheet l.

(Application led July 80, 1900.)

(Nu Model.)

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No. 664,440. Patented nec. 25, |900. w. scHuLTHEss.

APPARATUS FOR SLAKING LIME.

(Application led July 30, 1900.1 4 (No Model.) 3 Sheets-Sheet 2.

No. 664,440. Patented Dec. 25, |900.

W. SCHULTHESS.

APPARATUS FUR SLAKING LIME.

(Application led July 30, 1900.)

(No Modal.) 3 Sheets-Sheet 3.

UNITED STATES PATENT FEICE.-

WALTER SOHULTHESS, OF ZURICH, SWITZERLAND.

APPARATUS Fon SLAKING LIME.

v SPECIFICATION forming para of Letters Eaten@ No. 664,440, dated December 25, 1900. Application tied my so, 1900. serai No. 25,304. dit model.)

T0 all whom t nutyooncern:

Be it known that I, WALTER ScHULTHEss, a citizen of the Republic of Switzerland, residing at Zurich, Switzerland, have invented certain new and useful Improvements in Apparatus for Slaking Lime; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to letters of reference marked thereon, which form a part of this specification.

The slaking of burnt lime to form calcium hydrate in the form of powder is usually effected by placing it in heaps, sprinkling it with approximately the necessary quantity of water, and leaving it to itself for a protracted period of time. The burnt lime, if the proper quantity of Water has been added, is converted by the resulting slaking into powder, the reaction being accompanied by great evolution of heat. The powder varies greatly as to its chemical capacity to combine with sand according to Whether a greater or smaller quantity of water is employed, since it contains water in greater or less quantity combined physically and possibly chemically. Thismethod of slaking requires a considerable period of time for carrying it out. Moreover, it always yields a product partially decomposed by atmospheric carbonic acid, and Vits quality is wholly dependent on the degree of care with which the slaking is effected. It is hardly possible to obtain complete slaking by this method, as the mass cannot be frequently shoveled over, because of the immense amount of dust produced.

The mechanical apparatus hitherto employed for slaking lime consist either of cylinders which are provided with simple stirring appliances and in which the burnt lime is slaked with water or of pressure-chambers into which the burnt lime is run in trucks and after the chambers have been closed subjected to the action of high-pressure steam. In the rst case it is impossible correctly to apportion the quantity of Water requisite for slaking the lime, both on chemical and physical grounds, andv the result is that either part of the lime is not slaked at all or is Vwetted too much, so that a lumpy product is obtained, which in many cases is quite useless.' The method of slaking the lime in trucks in a pressure-chamber is very incomplete, as under these circumstances any turning over of the mass is utterly out of ques tion and the lime has to be brought in in trucks to prevent the calcium hydrate pro duced from becoming wetted by the conden-` sation-water running down the walls of the chamber, and consequently becoming lumpy. This method of slaking in pressure-chambers, moreover, is not only very complicated, but also very expensive, and for these reasons has not been able to make way in practice. Now in my apparatus slaking that has been only partially eected with water is complet-ed by adding hot aqueous vapor or steam, (hereinafter referred to as steam.) This slaking is carried out in a vessel surrounded on all sides by a jacket-space heated to at least 97 centigrade. This prevents steam from condensing in the vessel containing the lime, so that even if an excess of steam is admitted no possible injurious eects can result, as hereinbefore described.

An example of apparatus according to this invention is represented in the accompanying drawings, in which like parts are similarly designated.

Figure 1 is a vertical longitudinal section; Fig. 2, a top plan view; Fig. 3, a vertical cross-section through the hopper, and Fig. 4 an end view.

A horizontal or approximately horizontal` cylinder at, closed ou all sides and made of thin sheet-iron, carries at one end a hopper b, with which it can be placed in communication by means of a smallfsheet-iron box c, mounted on pivots a. vThis iron box is lled .with badly conducting material, as sawdust or ashes, or it may be filled with steam. In the latter case the steam is advantageously admitted at one end of the axle and allowed to escape at the other.

d represents a small sliding catch provided with a handle for keeping the box c closed;

In its lower part the cylinder ct is traversed throughout its whole length by a shaft e,'on

which mixing and conveying blades f are tion can be imparted by suitable means.

by means of driving-pulleys 71, and z', which can be rotated in opposite directions,

y represents a loose pulley. 4

At the opposite en d to the hopper the cylinder ct has an opening 0, which can be closed by means of a hinged door la (see Fig. 4t) and from which leads a sheet-metal chute Z, Fig. l, through which the iinished product can be delivered. This? cover la may likewise be formed of a small iron box filled either with some badly-conducting material or with steam admitted by a pipe passing through its axle. The condensation-water is led off through the other end of the axle. The cylinder ct is also provided with an opening m, that can beV closed by a sliding valve n, and with a waterpipe q, furnished with a Valve p and provided with rose-like or jet perforations.

rrepresents a steam-pipe that can be closed by means of a valve. l

In the upper part of the hopper b is arranged a shaker-sieve cc, to which reciprocating mo- The hopper b can be closed, so as to be dust-tight, by means of a lid fu, mounted on hinges.

The rst cylinder a is on all sides surrounded by and separated by a chamber or jacketspace s from a second and separate cylinder A, also of sheet-iron and made steam-tight in any suitable manner. Beneath and advantageously near to the steam-pipe r the cylinder A is provided with an escape-pipe u. w represents the pipe for carrying off the condensation-water and steam escaping from the pipe u. .The cylinder A is also provided in the middle with a steam-valve V, by opening which the space s can be filled with steam. The closing of the opening o by the cover 7c,

as well as that of the'valve c, should be as perfect as practicable.

The mode of operation of this apparatus is as follows: A definite charge of burnt limethe charge is always of the same amountis placed on the sieve :n (the valve c having been first closed) and sprinkled with` a portion of the quantity of water (previously calculated) approximately necessary for slaking it, and the lid Uisthen closed. In a short time the lime is partially slaked-i. e., it has fallen into a mixture of ne powder and larger pieces. By operatingthe shaker-sieve, which is mounted on rollers, the finer portions are separated from the larger pieces, which also fall through the siever after being again sprinkled with water. When this has been accomplished, the valve V is first opened until a small quantity of steam escapes from the pipe u. Then the valve c is opened, and thesliding damper n being closed the mixing and conveying blades are set into motion by means of the driving-pulley 't'. The lime is thus carried forward in the cylinder a (the valve la being closed) and spread out therein fairly uniformly. The pulley is then thrown-out of gear, and after opening m and closing V the remainder of the quantity of water herewater, it escapes slightly from the opening fm. 4

The contents of the vessel aiare mixed together from time to time (the steam-pipe r and the damper fn being closed) by working the mixing and conveying blades first forward and then backward. The steam-pipe and the damper must be kept closed, as otherwise the motion ofthe mixing-blades Would drive the very fine and quite dry calcium hydrate into the space between the cylinders and there form a crust, which, however, could be easily removed. When the slaking operation has been completed by alternate mixing and addition of steam, the lime-receptacle is emptied by the chute Z by setting the pulley z' into motion. The calcium hydrate is conveyed by means of an elevator to a sifting-machine, which separates out any particles of unburnt lime that may be present. The whole operation of slaking can be carried out without raising any dust, and only gross neglect can endanger the high quality of the resulting product.

Slaking such as hereinbefore described may be effected with the'aid of superheated steam, whether under pressure or not under pressure. In the irst case both cylinders are constructed as pressure vessels and made to close steam-tight and the inner receptacle is not provided with means for communicating with the jacket-space. `When superheated steam is employed, whether under pressure or not, the temperature of the jacket-space must at least be equal to that of the Vessel containing the lime. In some cases thejacketspace may even be heated to a higher temperature than that of the lime-containing vessel.

Having now particularly described and ascertained the nature of my said invention and in what manner the same is to be performed, I declare that what I claim is- 1. A mixing apparatus, comprising a suitable Vessel, a hopper organized to dump its charge into said vessel, means in said hopper for sifting material and a conveyer arranged to move material from end to end in said vessel, substantially as set forth.

2. A mixing apparatus, comprisingasteamjacketed vessel, a hopper at'one end thereof, a dumping-bottom for said hopper and a shaking-screen above the bottom, means for supplying water and steam to the vessel and a conveyer organized to carry material from end to end in said vessel, substantially as set forth. p

3.' A mixing apparatus, comprising a jacketed vessel, a hopper organized to dump into IOO IIO

said Vessel, a conveyer in the bottom thereof arranged to carry material from end to end in said vessel and means for feeding Water to the material in the conveyer, substan tially as set forth.

4. A mixing apparatus comprising a jacketed vessel, a hopper at one end thereof or-V ganized to dump into said Vessel, a jet-pipe in the latter, a conveyer organized to carry material from end to end under said jet-pipe and'means for discharging gases formed during mixing into the jacket-space of said Vessel, substant-ially as set'forth.

5. A mixing apparatus comprising a jacketed vessel, a closed hopper organized to du mp into one end thereof, a jet-pipe Within the vessel extending from one end to the hopper, a conveyer in the bottom of said vessel arranged to carry material from end to end of the Vessel under the jet-pipe, mea-ns for discharging gases formed during the mixing into the jacket-space and means for admitting steam into the vessel and jacket-space, sub-MM stantially as set forth.

6. A mixing apparatus comprising a jack= eted vessel, a closed hopper at one end thereof, means for sifting and dumping the hop- "per charge into the vessel, a steam-supply for WALTER SCHULTHESS.

Witnesses:

EMIL BLUM, A. LIEBERKNECHT. 

